All gem substitutes for InfraRuby are available under the MIT license, for example:

siphash-ir

Some other related packages are also available under the MIT license, for example:

meta-ruby

The only InfraRuby packages under proprietary licenses are infraruby-core-compiler and infraruby-core-runtime. The full text of these licenses can be found in these packages. We may vary the terms of these licenses from time to time, but these packages will always be available at no cost for open-source projects and personal use.

ragelCopyright (C) 2002-2006 Adrian Thurston <thurston@cs.queensu.ca>Source: http://www.complang.org/ragel/License:You may use the parts of Ragel output copied from Ragel source without restriction. The remainder of Ragel output is derived from the input and inherits the copyright status of the input file. Use of Ragel makes no requirements about the license of generated code.

ragelCopyright (C) 2002-2006 Adrian Thurston <thurston@cs.queensu.ca>Source: http://www.complang.org/ragel/License:You may use the parts of Ragel output copied from Ragel source without restriction. The remainder of Ragel output is derived from the input and inherits the copyright status of the input file. Use of Ragel makes no requirements about the license of generated code.